Heterogeneity and Controlling Factors of Oxfordian Stage Carbonate Reservoir of Odjarly Gas Field, Amu Darya Basin

摘要

Based on core observation and thin section authentication, the control factors of Oxfordian Stage carbonate reservoir of Odjarly Gas field of Amu Darya Basin were discussed by comprehensive utilization of geological, drilling, seismic data etc. It was concluded that the carbonate reservoir developed mainly in grain limestone, oolitic limestone and conglomeratic bioclast limestone. Lithology controlled directly the porosity of reservoir, and the porosity of grain limestone was the highest. The analysis showed that the carbonate reservoir quality of the Oja-21 was under the control of the sedimentary microfacies. The oolite beach and microfacies of bioherm phase were the favorable to develop. The physical property of oolite beach was optimal, and it was the most favorable sedimentary microfacies of reservoir development. It concluded also that the heterogeneity of core section of carbonate reservoir of Oja - 21 was mainly controlled by lithology, sedimentary microfacies and diagenesis. As for the core section, the heterogeneity of reservoir could be summarized as interbedded heterogeneity and in-layer heterogeneity.